Process for manufacturing dextrin.



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PROCESS FOR-MANUFACTURING DEXTJRTN.

Specification of Letters Patent.V V

Application iiled July 20, 1915, Serial No. 44,010. Renewed April 27, 191%. Serial No. 231,282.

To aZZ whom it may concern:

Be it known that l, WILLIAM W. Mc- LAURIN, a subject of the King of Great Britain, and a resident of- Brookfield, in the county of Worcester and State of Massachusetts, have invented an Improvement in Processes for Manufacturing Dextrin, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the dra-wings representing like parts.

This invention has reference to an improved process 4for manufacturing dextrin which maybe employed as an adhesive or for anyother purpose for which the dextrin 4of commerce is adapted to be utilized.

@ne of the objects of this invention is to so treat starch that such starch is converted into dextrin at a stage of hydrolysis at which the higher hydrolyzed intermediates are present, if at all, in negligible quantities.

Another object of the invention is to control the rate of speed of the process.

Other objects of the invention will appear from the following description. v

The invention consists in the novel and improved process for manufacturing dextrin as shall hereinafter and pointed out in the claims;

In the ordinary process of producing dextrin by the conversion of starch, by the Wet process, starch and water With a small 'quantity of hydrochloric, sulfuric, acetic or other open vesseland the ingredients are stirred. At the same time steam is injected into the mass which in additionto supplying heat thereto adds an uncertain quantity of water. After the point of conversion is reached the fluid is concentrated and eventually substantially all be more fully described of the moisture is evaporated, thus producing a comparatively hard material which requires the addition of water to reduce it to a consistency for use as an adhesive or `for otherpurposes to which commercial dextrin is adapted.

ln carrying my invention to practice one of my principal objects is tov produce a dextrin ready to use as an adhesive or for other purposes without the addition of water. This requires that during the operation of my process the dextrin should have a greater degree of concentration than during the processes heretofore employed and at which degree 'of concentration, the starch would not be completely accomplished rubbery condition Van adhesive v on conversion of the without the assistance of certain steps in my process.

In carrying my improved process for manufacturing dextrin into operation utilize a vessel having a steam jacket said vessel from 'its construction or operation be` ing adapted to agitate or mix the contents thereof. Into this vessel T place approximately equal or suitable quantities of water and starch of any known kind and a small quantity of oriilnay assist in the breaking up of thestarch ce s. steam to the jacket thereof, whereby the temperature of the contents of the vessel is raised and ultimately after the temperature of said contents reaches 212 F. pressure is whereby convection is assisted. This agitation or mixing of the materials reduces the tendency' of the formation of the tough, rubbery material ordinarily caused by the partial hydrolyzing of the starch, so that as the conversion proceeds the mixture -is rendered smooth and reaction of the fluid but comparatively syrupy mixture toward a is avoided to a large de, gree but particularly after the critical temperature of about 230 F. is reached. After suitable conversion vof the starch substantially at a point at which approximately 10% of sugar is present ll'varrest the process of conversion and reduce the temperature of the material.'

The dextrin thus produced will contain a degree of acid which is not objectionable for many purposes and as a matter of fact for some purposes the presence of said acids and protein is desirable but for some other' purposeswhere the dextrin is to be used as ldelicate materials it is desired to neutralize the acid to some extentand this is accomplished in any known manner.

In order to more clearly describe the princ'iple of the presentlinvention I have shown in .the accompanyingl drawings, and shall hereinafter describe, a machine adapted for use in carrying lout i Figure 1 Ais a vertical longitudinal, central `section embodying one form of appara-1 tus by which the process may be practised.

2 is a transverse section thereof.

detail in section upon an en- Fig."

Fig. '3 is a suitable acid which latter assists-4 T next close the lvessel and'supplythis improved process.

patented not. a, iai.

larged scale taken through one of the steam circulating pipes. i

My invention relates to the manufacture of dextrin from starch, to which end I employ any suitable starch and water. The starch may be obtained from corn, potato, salgo, tapioca, or any other desired or suitable material. In carrying out my process, I preferably take equal parts of starch and cold water, making them into a smooth cream, free from all lumps. To this, I add a suitable acid, preferably in a small amount. I have obtained excellent results by employing a one-thousandth part of concentrated hydrochloric acid (specific gravityLlQ), that is, one tenth of one per cent. of the Weight of the starch. This may in some -cases be somewhat increased, the maximum being substantially three tenths of one per cent. of the weight of the starch. These figures are illustrative merely and are not given for purposes of precise limitation. These ingredients may be mixed either outside of or within the conversion chamber represented in the accompanying drawings, and which I will now specifically describe.

The said conversion chamber is herein represented as a closed vessel 1 of any suitable material having an acid resisting lining f2, preferably formed of lead. The said vessel is provided with a jacket 3 entirely surrounding the same for the reception of live steam which may be admitted through an inlet pipe 4 and discharged from an exit pipe 5. The said vessel is provided with trunnions 6, 7 received in or upon suitable bearings 8, 9, the steam inlet and exit pipes passing through said trunnions. I preferably rotate said vessel or digester, and herein for that purpose have represented a worm gear l() fast on the trunnion 6 and meshing with and driven by a worm l1 on a shaft l2 havingthereon fast and loose pulleys 13. The vessel or digester is provided with a man-hole let of any suitable construction and by means of which the described material may be placed within the vessel or digester. At some suitable point, and as herein shown, at a point opposite the man hole 14,- I provide a discharge opening l5 provided with a gate-valve lt by means of which the contents may be withdrawn as 'quickly as possible, so that when the process is finished. the material may be run ofi1 before further conversion thereof takes place. Preferably I provide a smaller opening 17 having a pet-cock 18 to permit the drawing off of samples of the 'liquid during the carrying out of the process. In this manner, I may determine at any time j ust what stage of the conversion has been reached. Either the steam inlet or the steam outlet pipe is provided with a suitable safety valve, pressure gage and thermometer, the construction being such that I may permit the blowing ofi' of the steam very rapidly, so as quickly to reduce the pressure within the vessel at any desired stage in the carrying out of the process.

The vessel l is provided with any suitablef number of pipes extendingl therethrough in any desired direction. I have in the drawings represented four pipes respectively arranged in pairs at right angles to each other and of which the. pipes 19, 2l and 23 are 'ing 2.V I have herein represented each of said pipes as having threaded ends 21' rcc'eiving nuts 25, 26 for securing them in position.

The said pipes perform the double purpose of assisting the breaking up of the material and the mixing thereof` during the rotation of the vessel or digester, and also the bringing of the steam into more intimate relation with the mass within the vessel or digester. It is to be understood, however, that the steam within the Jacket or pipes does not come in direct contact with the material. The said pipes therefore assist in the uniform conversion ot' the matcrial. Any suitable number of pipes may be employed, and their arrangement. may be varied within the scope of in v invention. The illustrative digester constitutes` the preferred embodiment of means for practising my process, but any other suitable means may be employed for carrying out said process.

I have previously stated that approximately equal parts of starch and cold water are mixed, and that I add a preferably small quantitv f hydrochloric acid. The 'vessel is closed after being` charged with. said material, and by the introduction of. .steam through the inlet )ipe al, the heat is raised as quickly as possi le, preferably to :284 F. (140 C.) with preferably substantially 524; pounds steam pressure. While the relativo proportions of the starch and water may be varied somewhat it is to be understood that a fluid product of somewhat high concentration is desired and the miantities of water used are proportioned to obtain this result. In the early stages of hydrolysis the lstarch tends to form a comparatively tough, highly viscous substance or n'iass which resists conveetion and conversion. In order to overcome such condition the vessel i s caused to rotate whereby the contents are subjected to a degree of centrifugal action as well as to the mixing action of the cross pipe members- 15), 21, Q3 whereby the contents of the vessel are so disturbed that the thorough hydrolyzing of' the starch and a consequent uniformity in viscosity of the material rein the practice concentration with the mechanical mixing.

' In the claims I state that substantially equal quantities of commercially pure starch and water are employed. 'By this I mean that the two substances may be varied not lmore than ten y exalnple 60% starch and 40% water. The mixing of the substances occurs while the same' are subjected to the-indirect action of steam. I am not limited to the mixing at any particular time.

I do not-herein claim either the product resulting from my process or the apparatus herein shown for carrying out said process, the same being the subject matter of other applications.

By myprocess, all the starch is converted into dextrin at a stage of hydrolysis at which the higher hydrolyzed products, namely, maltose and dextrose, are present, if at all, in such small quanitities as to-be negligible, the maltose being in combination with malto-dextrin.

The dextrin produced by my process of conversion may contain a comparatively small amount ofacid and protein which for some purposes for which dextrin can be used, may be desirable. When the improved dextrin is to be used as an adhesive to be f applied to delicate fabric or material which is liable to injury from such acid the acid can be neutralized in any known manner.

I control the rate of speed of the process by employing a small amount of acid, so that the reaction goes on at a safe speed and enables me to remove` the productfrom the apparatus before there is formed any undue proportion of after products.

The solution formed as the result of my process constitutesa paper coating which is substantially free from hygroscopic effects,

owing to its essential freedom from the higher converte-d products ordinarily present in dextrin as made by the usual methods,l

. namely, maltose and `dextrose and their combinations. f

Having thus described my invention and the best mode known to me for carrying out the process thereof, I desire it to be underl stood that although speciicterms are employed., they are used in a generic and descriptive sense and not for purposes of limitation, the scope of the invention being set forth in the following claims.

' No claim is made herein to the productv produced by the process as set forth, the same being reserved for and forming the continuing the process per cent. either way, as for .vessel before 'sel them to the indirect action of steam, thereby to obtain a 1. That process of manufacturing dextrin as a solution or liquid comprising placing equal parts of starch and cold water and a thousandth part of concentrated hydrochloric acid in a closed vessel, raising the temperature of said contents to substantially 284 F mixing the contents of said vessel,

until the desired approximation to perfect dextrin is obtained and Withdrawingthe resulting solution.

2. That process of manufacturing dextrin as a solution or liquid comprising placing yequal parts of starch and cold water and a thousandth part of concentrated hydrochloric acid within a closed chamber, eecting a thorough mixing of said contents, raising the said contents to atemperature of substantially ,284 F. by the indirect application of steam heat, thereby subjecting the starch to a high degree of pressure, rapidly withdrawing said pressure and removing the resulting solution.

3. That process of producing substantially perfect, concentrated dextrin in the form of a solution or liquid, which comprises placing substantially equal quantiti'es of commercially pure starch and water with a small quantity of acid within a closed conversion is effected, subjecting them tothe indirect action of a heating agent, thereby to obtain a high pressure upon the starch during the treatment thereof, and mixing the mass.

4. That process of producing substantially perfect, concentrated dextrin in the form of a solution or liquid, which comprises placing substantially equal quantities of commercially purestarchand Water with i a small quantity of acid within a closed vesbefore conversion is effected, subjecting action of steam, and thereby raising the temperature of the con tents until the same is brought to a suiiciently liquefied condition to permit mixing, and effecting the application of a high degree of pressure, and mixing the mass.

5. That process of producing substantially perfect, concentrated dextrin in the form of a solution or liquidI which comprises placing substantially equal quantities of commercially pure starch and water with a quantity of acid of the hydrolytic equivalent of less than one per cent. of hydrochloric acid on the weight of the starch, within a closed Vessel before conversion is effected, and subjecting them to the indirect hi h pressure upon the starch during the tregtment thereof, and mixing the mass.

6. That process of producing substantially perfect, concentrated dextrin in the form of a solution or liquid, which com- I lthe indirect action of steam,

all)

taeaeae prises placing substantially equal quantities of commercially pure starch and Water with a quantity ofi-acid of a hydrolytic equivalent of less than one per cent. of hydrochloric acid on the weight of the starch, Within a closed vessel, subjecting them to and thereby raising the temperature to at least'ZOO F., thereby to eect the liquecation of the starch necessary for mixing and for the production of a homogeneous product, and mixing the mass.

7. That process of producing substantially perfect, concentrated deXtrin in the form of a solution or liquid, Which comprises placing substantially equal quantities of commercially pure starch and Water with a quantity of acid materially less than one per cent. of the weight of the starch Within a closed vessel, raising the temperature of said contents to at least 230 F., thereby to effect the liquefication of the starch necessary for miXing it, and thereby effecting the application of a high degree of pressure, raising the temperature to a point between 250 F. and 300o F., and mia?- ing the mass.

8. 'lhat process of producing substantially perfect, concentrated deXtrin in the form of a solution or liquid which com `prises placing substantially equal quantities of commercially pure starch and Water together With a quantity of concentrated hydrochloric acid materially less than one per cent of the Weight of the starch Within a closed vessel, subjecting them to the indirect action only of steam, thereby to raise the temperature above 230 F., thus obtaining a high pressure upon the steam during the treatment thereof, mixing the contents and continuing said pressure until eecting thereby the uniform and homogeneous change in the entire starch contents, and whereby a fully converted deXtrin is obtained in the form of a colorless solution, liquid at 60O to 70 F.

9. 'llhat process of producing substantially perfect,` concentrated deXtrin in the form 0f a solution or liquid, which comprises placing substantially equal quantities of commercially pure starch and Water together with a quantity of acid materially' 280 F.. thus obtaining a high pressure upon the starch during the treatmentthereof,

mixing the mass and continuing said pres-l sure until effecting thereby the uniform and homogeneous change in the entire starch contents, and whereby a fully converted dextrin is obtained in the form of a colorless solution, liquid at 600 to 70(J F.

- l0. That process of producing deXtrin which consists in taking suitable proportions of starch and cold Water, mixing them into a comparatively smooth cream, adding thereto a suitable acid, placing said acidulated cream in a vessel before. hydrolysis is effected, closing said vessel to retain pressure generated therein, operating upon said cream mechanically to disturb the same, and subjecting said vessel to heat to generate pressure therein.

11. That process of producing dextrin which consists in taking suitable quantities of starch, Water and acid and makin a comparatively smooth cream thereof, con ning the same before hydrolysis is effected, and effecting the mechanical mixing thereof under pressure generated from indirect heat.

l2. 'lhat process of producing ready to use dextrin substantially uncolored which consistsin taking starch and Water in proportions determined by the purposed degree of concentration of the dextrin, adding a small amount of acid and mixing the substance to make a comparatively smooth cream thereof, confining such cream to prevent the access theretoof air and the escape therefrom of steam, subjecting the same' to indirect heat during a suitable period, and reducing the pressure and temperature of the converted substance.

ltn testimony whereof, l have signed my name to this specification, in thepresence of tvvo subscribing Witnesses.

WlliLlAlMl W. MGLAURTLN.

Witnesses:

L. A. Bassnfr'r, H. ll/l. DONAHUE. 

